This invention relates to a ski binding. It relates more particularly to an adapter that permits a skier's boots to be clamped to the same ski in the two different ways required for downhill and cross-country skiing.
When skiing downhill, both toe and heel of the skier's boot should be clamped to the ski so that there is essentially no relative movement between the wearer's foot and the ski. To achieve this result, the usual downhill ski boot has a relatively thick sole that is quite rigid. The boot is secured to the ski by a binding that includes a clamp device that engages over the protruding front edge of the shoe sole and a second clamp or spring that engages the heel of the ski boot. Thus the boot is retained to the ski both at its front and rear ends. In some cases, these clamps release automatically when subjected to an unusually high torque or lateral thrust that occurs when the skier falls the wrong way. This enables the boot to separate from the ski minimizing the chances of injury to the skier.
In cross-country skiing, which involves climbing and traversing, as well as some downhill skiing, it is desirable for the skier to be able to flex his foot up and down on the ski to achieve optimum control during the different situations encountered in cross-country skiing. To this end, the cross-country ski boots usually have relatively flexible soles. The boot is secured to the ski by a binding that engages around the protruding side and forward edge margin or welt of the boot sole. Relative sliding movement between the boot and ski is prevented by one or more pegs which project up from the top of the ski into mating openings in the underside of the boot sole.
Normally a given ski has either a cross-country binding or a downhill binding permanently attached to the ski. Therefore as a practical matter that ski is dedicated to either downhill or cross-country skiing because a cross-country binding cannot retain the heel of a ski boot and the downhill binding which normally retains the heel of the boot does not have any means for preventing sliding between the boot and ski should the boot heel retainer be omitted.
There do exist some special binding mechanisms for permanent attachment to skiis which can be adjusted by a skier while standing on the skiis so that, in one position, the heel of the boot is secured and in a second position, the heel of the boot is free. Such bindings are shown, for example, in U.S. Pat. Nos. 2,831,696 and 3,951,424. However these devices are relatively complex and therefore expensive. Also in some cases, they make no provision for releasing the skier's boot in the event of a fall. Additionally, since the skier must typically change his boots when switching from downhill to cross-country skiing, the fact that such mechanisms can be adjusted by the skier while standing on the skiis represents no real advantage.